How To Perform The Best Heat Treatment On Files
The heat treatment process of the file is as follows: heating-cooling-heat straightening-cooling to room temperature-cleaning-tempering-cleaning-inspection. During the preparation and operation of the heat treatment process, preventing tooth quenching and decarburization and having skilled straightening techniques are the keys to file heat treatment. Therefore, high-frequency induction heating is generally carried out, or treatment in a controlled atmosphere furnace, if there is no condition, It can be carried out in a salt bath furnace containing yellow blood salt. The general composition of yellow blood salt is: sodium chloride 50% + yellow blood salt 35% + sodium carbonate 15%. According to the information, the composition of yellow blood salt can fluctuate in the range of 10% to 40% in the actual heating process.
The heat treatment process is as follows:
- The heating temperature is 750~790?, and the holding time should be selected correctly according to the different heat treatment equipment.
- The cooling medium is 10% salt water or flowing clean water, and the temperature should be lower than 30°C to ensure sufficient cooling performance and high hardness for the file.
- The low-temperature tempering of the file is usually carried out in a nitrate furnace, the temperature is 160-180?, and the time is 60-90min.
- The file is cooled to the range of 180~200? in the cooling medium, and it should be taken out and straightened by hand immediately. The file is straightened in a short period of time and then put into the medium to cool it through, and it is completely hardened.
- There are four ways to reduce the hardness of the handle: one is to heat the handle in a salt bath furnace for a short time and then it is oil-cooled; the other is to temper the handle at about 500? and then cool it in oil; the third is to The handle is subjected to high-frequency induction heating; when the final quenching is used, the teeth of the file are filled with water first, and the handle is cooled as a whole when it is dark red.
- The cooling technique of the file. The arc part of the semicircular file is easy to bend to the inside when it is cooled, and it is pre-deformed; or the arc face downwards and enters the water at 45° with the medium. For flat files, round files, triangle files, and square files, they are placed perpendicular to the liquid surface.
- The straightening temperature of the file should be controlled correctly, the hardness of the file will be low if the water is discharged early; the water will be difficult to straighten if the water is discharged late, and even cracks and breaks may occur.